Global Maxwell Tomography for Tissue Electrical Property Mapping
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Solution Overview
Problem
Current magnetic resonance techniques fail to accurately and non-invasively determine the spatial distribution of electrical properties of human tissues, particularly in high-frequency applications, due to limitations in spatial resolution, edge artifacts, and reliance on symmetry assumptions, which hampers effective cancer detection, hyperthermia treatment, and RF safety assessment.
Innovation Solution
Global Maxwell Tomography (GMT) uses a volume integral equation-based approach to iteratively simulate and adjust electrical property estimates, leveraging RF electromagnetic waves and MR signals to determine tissue electrical properties with high spatial resolution, avoiding edge artifacts and symmetry assumptions, and incorporating transmit and receive phases for better numerical conditioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional magnetic resonance techniques are used to determine electrical properties of tissues, then the measurement process is simplified, but the spatial resolution deteriorates and edge artifacts increase
Solution Approach 1:
The patent segments the measurement process into multiple independent projections acquired from different transmitter-receiver coil pairs. Each projection provides partial information about the electrical properties, and these segmented measurements are subsequently reconstructed into a complete high-resolution image using iterative algorithms, thereby achieving high spatial resolution without requiring a single complex measurement setup
Solution Approach 2:
The patent transitions from local two-point measurements to global three-dimensional tomographic reconstruction. By acquiring measurements from multiple coil pairs at different spatial positions and reconstructing them using iterative algorithms, the system achieves high spatial resolution throughout the entire volume, eliminating the resolution limitations of conventional local measurement techniques
2Device complexity
If conventional magnetic resonance techniques are used to determine electrical properties of tissues, then the measurement process is simplified, but edge artifacts increase
Solution Approach 1:
The patent implements an iterative feedback mechanism where initial estimates of electrical properties are used to simulate expected measurements, these simulations are compared with actual measured projections, and the estimates are refined based on the differences. This feedback loop continues until convergence, effectively eliminating edge artifacts by ensuring consistency between measured and simulated data at all spatial locations including edges
Solution Approach 2:
The patent combines multiple measurement modalities and data sources into a composite measurement framework. By integrating measurements from multiple transmitter-receiver coil pairs and combining them through iterative reconstruction algorithms, the system creates a composite view that eliminates edge artifacts through mutual validation and consistency checks across different measurement pathways
3Device complexity
If conventional magnetic resonance techniques are used to determine electrical properties of tissues, then the measurement setup is simplified, but the ability to detect cancer deteriorates
Solution Approach 1:
The patent segments the detection task into multiple specialized measurements from different coil pairs, each optimized for detecting specific tissue characteristics. By combining these segmented measurements through iterative reconstruction, the system achieves comprehensive cancer detection capability that surpasses any single conventional measurement approach while maintaining practical system complexity
4Measurement precision
If iterative simulation and adjustment of electrical property estimates is performed, then measurement precision improves, but productivity deteriorates
Solution Approach 1:
The patent performs preliminary actions by acquiring all necessary projection measurements from multiple transmitter-receiver coil pairs before initiating the iterative reconstruction process. This allows the iterative algorithm to work with complete data sets, converging faster and achieving high precision without requiring repeated measurements, thereby balancing measurement time with accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
GMT enables accurate, non-invasive determination of tissue electrical properties with high spatial resolution, improving cancer detection, hyperthermia treatment planning, and RF safety assessment, while avoiding the limitations of existing techniques.
Implementation Method 1
transmitting, to the at least one target, a plurality of stimulations via one or more transmitters, measuring signals associated with the stimulated target
Data Source
AI summary
A plurality of stimulations is transmitted to tissue or other material using one or more transmitters. The plurality of signals associated with the excited tissue and the transmitted stimulations are measured. The measured signals are processed to generate field-related quantities, such as B1+ and/or MR signal maps. Field-related quantities are generated also from simulation, by calculating the one or more incident fields from a simulator model of the one or more transmitters and assuming a given distribution of electrical properties in the tissue or other material. Field-related quantities generated from simulation and experimental procedures are compared to each other. The assumed electrical properties distribution is updated and the procedure is repeated iteratively until the difference between simulated and experimental field-related quantities is smaller than a threshold.